The purpose of the buttons does not depend on the firmware version.
S1 “Barrier -” / “Guard interval-“
S2 “Barrier +” / “Guard interval +”
S3 “Volume -” / “Up min-“
S4 “Volume +” / “Up min +”
S5 Function not yet assigned.
S6 “Zero” (0)
S5 + S6 “Settings Mode” / “Exit Settings Mode”
Barrier buttons : S1 – minus, S2 – plus. The barrier raises the threshold at which the signal from the analog part of the device is perceived as the presence of a target. Thus, increasing the barrier, we raise the response threshold of the metal detector to the metal, thereby lowering the sensitivity. In other words, the higher we expose the barrier (more LEDs) – the lower the chuik on the metal and the fewer false alarms. The set value of the barrier is remembered even after the power is turned off. The value of the barrier does not affect the magnitude of the protective interval (ZI). The protection interval is set automatically every time the power is turned on (the microcontroller calculates the ZI depending on the circuit settings, coil parameters and the environment). The ZI value can be changed manually in the settings mode using the barrier adjustment buttons, but this is meaningless and in practice no one ever does that. After the power is turned off, the ZI value is not saved.
Volume : S3 – minus, S4 – plus (maximum level – 7). In the settings mode, these buttons set the minimum permissible supply voltage (from 7.5 to 11V, step – 0.5, the default is 8 Volts). When the voltage drops below the set level, the device will continue to work, but at the same time every 15 seconds there will be a characteristic low-frequency signal.
S5 button – enter settings mode (not in all firmware versions). If you make a metal detector not for yourself, then it is better not to put this button at all. In order not to seduce once again.